The GZIP sizes are for the files as downloaded from the EBI Mirror FTP site in early September 2011. I then decompressed them, and re-compressed as BGZF using bgzip from samtools, or as bz2 using bzip2. I presume that both the original GZIP file and the BGZIP file are using the same default ZLIB compression settings. As I noted before, the 64kb block size currently used in BGZF is hurting it in th